Thus, when a person swears an oath regarding something, the preferable course is not to break that oath but to remain upon what he swore. If, however, he swears to abandon an obligation, he must break the oath and make expiation. Take, for instance, the one who says, “By Allah, I will not pray in congregation today.” This is unlawful, for joining the congregational prayer is obligatory. Such a situation can arise: a father tells his son, “My son, go and pray,” and the son replies, “By Allah, I will not pray with the congregation today—just to spite you.” Some foolish people speak in this way. Once the oath has been uttered, we say to him, “That is impermissible; you must attend the congregation and then expiate for your oath.”
Another example: someone swears, “By Allah, I will not speak to my cousin,” because of a misunderstanding between them. This is likewise unlawful, for it constitutes severing family ties and shunning one’s brother. He must therefore be told, “Speak to him and expiate for your oath.”
Or consider the case in which a father instructs his son to pray the voluntary Zuhr prayer, and the son retorts, “By Allah, I will not pray it—just to annoy you.” Here it is recommended that he perform the prayer and expiate for his oath, though it is not obligatory, since the Zuhr supererogatory prayer itself is not required.
In summary: if someone swears an oath and later recognizes that another course of action is better, he should expiate for the oath and do what is better. He may, if he wishes, act first and then expiate, or expiate first and then act.
The compiler cites several hadiths on this issue, among them the narration of ʿAbd al-Raḥmān ibn Samurah (may Allah be pleased with him), in which the Prophet (peace and blessings be upon him) said, “If you swear an oath and then see that something else is better, expiate for your oath and do what is better.” That is the Prophet’s verbal instruction. His practical example is his statement: “By Allah—if Allah so wills—I never swear an oath and then see something better without expiating for that oath and doing what is better.” Thus, through both word and deed, it is established that when a person swears about something and later realizes that something else is superior, he must expiate for the oath and carry out what is better.
If no preferable alternative exists, it is better for him to keep the oath and not violate it, in accordance with Allah’s words: “and guard your oaths” (Qur’an 5:89).
Allah is the One who grants success.